The present invention relates broadly to surgical instruments and more particularly to methods and a device for collecting and removing specimens from a body cavity during surgery.
During surgery, there is often a need for the collection and removal of tissue specimens, such as organs or other material from a body cavity of the patient. These materials must generally be isolated to prevent contamination of the body cavity during removal. In minimally invasive surgery where access to the body cavity is restricted to vary small incisions, isolation and removal of specimens can be difficult. This is particularly so because such surgery often involves insufflation of the body cavity requiring that the access incisions be sealed against leakage.
The problem of specimen retrieval during minimally invasive surgery has typically been addressed by the introduction of a closable, flaccid bag or pouch into the body cavity. This pouch is typically deployed through a cannula and includes an arrangement for remotely closing the bag once a specimen has been deposited therein. Once closed, the pouch may be withdrawn through the cannula.
Several problems have been presented by previous specimen pouch designs, particularly with respect to their closure mechanisms. Because a specimen pouch must be closed prior to removal from the body cavity, its closure mechanism must be, in part, external to the patient's body. The mechanism often takes the form of a tether, drawstring or other flexible member that is threaded around the bag opening and through the cannula. Closure is typically accomplished by retraction of this member which results in the cinching of the pouch. With most such designs, the pouch must remain attached to this mechanism or to the cannula used to introduce the pouch. In either case, the introducer cannula must remain in place, typically with a portion of the closure mechanism disposed therein. This not only prevents the cannula from being used for other instruments, it restricts the movement of the pouch within the body cavity.
Another problem results from the manner in which the closure mechanism draws the pouch closed. Closure is usually accomplished using a form of cinch or noose wherein a drawstring or belt is drawn through a sleeve disposed around the opening of the pouch. This method often results in irregular bunching of the material around the pouch access opening which, in turn, can result in incomplete closure and an unacceptable risk of contamination. Further, nooses and other mechanisms used for closure require the drawing of a single strand or belt through essentially the complete circumference of a sleeve surrounding the bag opening. In addition to compounding the bunching problem, this results in an increase in the force required to draw the strand or belt through the sleeve as the bag nears complete closure.
Other specimen bag designs have attempted to solve the closure problem by using collapsible spring members or other relatively complex mechanisms that may require the use of specialized instruments to assist in closure.
There is accordingly a need for a specimen retrieval device that provides secure isolation of collected specimens using a low complexity, remotely manipulated closure mechanism that is separable from the collection device.